DESCRIPTION (applicant's abstract): Exposure to early adverse experience, including malnutrition, infection, abuse or neglect, is associated with sensitization of the hypothalamic-pituitary-adrenal axis such that even mild stressors later in life may have profound effects. Early exposure has also been proposed to increase the vulnerability to dysfunction in the regulation of reproduction and growth. The neuroendocrine circuits affected by early adverse experience remain to be identified, as does the cascade leading to the associated outcomes. The development of animal models would aid in our understanding of these processes and their potential remediation. In this proposal we will determine the effects of early maternal separation, coupled with long- term isolation on anthropometric assessments of growth as well as hormonal determination of growth and stress responsivity. We will assess the influence of these early experiences on the hypothalamic control of growth hormone release as well as the influence of known neurochemical pathways on the regulation of growth. The development and initial characterization of this animal model will allow us to begin to understand the influence of early deprivation on the development of children.